The present invention relates to mobile communications systems, and more specifically, to the administration of regional subscription restrictions (i.e. when a subscription is restricted to certain geographical zones) when a subscriber is roaming in a network including a Gateway Location Register (GLR). The present invention also relates to the application of the GLR in the mobile station terminating Short Message Service (SMS) application. The present invention further relates to the application of the GLR within packet switched networks.
FIG. 1 illustrates a wireless communication system in accordance with the Global System for Mobile communication (GSM) standard. The GSM standard is designed to provide a uniform interface which allows mobile communication subscribers of various countries to operate their mobile devices regardless of the current location of the mobile subscriber. A mobile subscriber typically has a subscription with a network which is designated as the mobile subscriber""s home public land mobile network 10 (HPLMN). The HPLMN 110 has a home location register (HLR) 115 which contains, among other things, various information regarding the services provided to the mobile subscriber. When a mobile subscriber roams into a different network, which is referred to as a visited public land mobile network 120 (VPLMN), the VPLMN requires certain data regarding the mobile subscriber""s subscription. The data regarding the mobile subscriber""s subscription is also known as the mobile subscriber""s profile. The mobile subscriber""s profile is transferred from the HLR to a visitor location register (VLR) in the VPLMN 120.
In a GSM system mobile subscriber data is stored within the VLR that is associated with the mobile services switching center (MSC) that currently serves the mobile subscriber in order to reduce internetwork signaling between VLRs and HLRs. The decentralization of the VLRs within a GSM system (i.e., each MSC being equipped with a VLR) reduces intranetwork signaling as well. So, for example, if the mobile subscriber is roaming in an area of the VPLMN 120 which is controlled by the MSC/VLR 130, the HLR 115 will transfer the mobile subscriber""s profile to MSC/VLR 130. Similarly, if the mobile subscriber is roaming in an area controlled by MSC/VLR 135, the HLR 115 will transfer the mobile subscribers profile to MSC/VLR 135. Although FIG. 1 illustrates the MSC/VLR as a single network node, one skilled in the art will recognize that the MSC and VLR can be implemented as separate network elements.
To increase the compatibility of GSM with other types of systems, it is anticipated that future versions of the GSM standard, also called Universal Mobile Telecommunications System (UMTS), will incorporate elements of other mobile communications systems. For example, the Japanese Personal Digital Cellular (PDC) system includes a network node which is used to reduce internetwork signaling known as a gateway location register (GLR). FIG. 2 illustrates an exemplary mobile communications system in accordance with the PDC system. Like a GSM system, a home network 210 includes an HLR 215 which contains the mobile subscriber""s profile. When a mobile subscriber roams into a visited network 220 the mobile subscriber""s profile is transferred to GLR 225. In GSM terms, the GLR can be described as a VLR for all mobile subscribers roaming from other networks. Hence, only one GLR is needed for each network.
FIG. 3 illustrates an exemplary UMTS system which incorporates the GLR of the PDC system. When a mobile subscriber of HPLMN 310 roams into VPLMN 320, the HLR 315 will transfer the mobile subscriber""s profile to GLR 325. Then, depending upon which area within the VPLMN 320 the mobile subscriber is roaming, the GLR 325 will transfer the mobile subscriber""s profile to the respective MSC/VLR 330, 335 or 340. The introduction of the GLR 325 into a GSM/UMTS system reduces internetwork signaling because once the mobile subscriber roams into VPLMN 320, the HLR will only need to transfer the mobile subscriber""s profile to GLR 325. GLR 325 will be responsible for transferring the mobile subscriber""s profile to the proper MSC/VLR within VPLMN 320 as the mobile subscriber travels around the VPLMN 320.
The protocol used by GSM/UMTS systems for transferring data between MSC/VLRs and HLRs is the mobile application part (MAP). Since GLRs are optional elements within the UMTS system, MAP procedures must be completely independent of the presence or absence of GLRs in a network. Accordingly, by using an HLR interface towards the MSC/VLRs and an MSC/VLR interface towards the HLRs, the GLR should be completely transparent. However, because of the dual nature of the GLR in the network it may be difficult for the GLR to behave in a way which simultaneously will be perceived as MSC/VLR behavior by the HLRs, and as HLR behavior by the MSC/VLRs. One such case is the administration of regional zone subscription restrictions.
The Technical Standard (TS) GSM 09.02 (ETSI ETS 300 974) standard, i.e. MAP, specifies the procedures for administration of regional subscription restrictions for GSM networks. FIG. 4 illustrates a conventional method for transferring regional subscription restrictions from an HLR to an MSC/VLR. In step 405 an MSC/VLR receives a location update request from a mobile subscriber. In response to the location update request the MSC/VLR sends a MAP_UPDATE_LOCATION message to the HLR associated with the mobile subscriber in accordance with step 410. In step 415 the HLR extracts the Country Code (CC) and the National Destination Code (NDC) from the VLR Number parameter, i.e., the E.164 number, in the MAP_UPDATE_LOCATION message which was sent from the MSC/VLR to the HLR. A Country Code identifies the country in which the PLMN is located and a National Destination Code identifies the PLMN in that country.
In step 420 the mobile subscriber""s HLR initiates the framed MAP_INSERT_SUBSCRIBER_DATA procedure to transfer relevant subscriber data to a new MSC/VLR. If regional subscription restrictions apply to the mobile subscriber, the MAP_INSERT_SUBSCRIBER_DATA message, or messages, will include the Regional Subscription Data parameter including Zone Codes indicating the geographical zones in which the mobile subscriber""s subscription is valid. A Zone Code is the last part of the Regional Subscription Zone Identity (RSZI) and it identifies a regional subscription zone as a pattern of allowed and non-allowed location areas uniquely within a PLMN. Using these Zone Codes, an MSC/VLR can unambiguously determine whether a subscriber is entitled to service in his current location, provided that all the location areas in the service area of the MSC/VLR are located in the same country.
If the network spans more than one country, a Location Area Code, and consequently also a Zone Code can be ambiguous within a single network. Such a network would have to have separate Country Codes and National Destination Codes for the parts of the network that are located in different countries. If such an international network uses only one single GLR or if at least one GLR serve more than one country, there will be a problem in the administration of regional subscription restrictions.
FIG. 5 illustrates an exemplary UMTS network where a GLR serves MSC/VLRs located in more than one country. The network includes a home public land mobile network (HPLMN) 510, VPLMN 540 located in one country and VPLMN 570 which is located in a different country from VPLMN 540. HPLMN 510 includes an HLR 515 for storing mobile subscriber data. VPLMN 540 includes a GLR 545 and MSC/VLRs 550, 555 and 560. VPLMN 570 includes MSC/VLR 575. In the network of FIG. 5 GLR 545 serves MSC/VLRs in two different countries, i.e., VPLMN 540 and VPLMN 570. VPLMN 540 and VPLMN 570 could also be regarded as a single PLMN spanning more than one country.
Conventionally, when a mobile subscriber roams into an area supported by MSC/VLR 550, a MAP_UPDATE_LOCATION message would be sent from GLR 545 to HLR 515 only upon the first location update request of a series of consecutive location update requests from the roaming mobile subscriber in the concerned visited network. In the resulting MAP_INSERT_SUBSCRIBER_DATA message from the HLR 515 to GLR 545, the Regional Subscription Data parameter would include a list of Zone Codes which does not include CC and NDC for the allowed zones in the visited PLMN in that country. If the mobile subscriber subsequently roams into an area supported by MSC/VLR 575 which is located in a different country from MSC/VLR 550, GLR 545 would receive the MAP_UPDATE_LOCATION message from MSC/VLR 575 and GLR 545 would reply with a MAP_INSERT_SUBSCRIBER_DATA message including data from its own subscriber data records for the concerned subscriber. The problem is that the list of Zone Codes that were stored in the subscriber data in GLR 545 were based upon the CC and NDC of VPLMN 540, and hence, are no longer valid in the new country, i.e., in VPLMN 570. Accordingly, the GLR, and in turn MSC/VLR 575, will not be able to determine the allowed zones in VPLMN 570.
FIG. 6 illustrates an exemplary UMTS network where a GLR serves multiple networks within the same country. The network includes HPLMN 610. The network also includes GLR-PLMN 620, VPLMN 630 and VPLMN 650 all located within the same country. HPLMN includes HLR 615. GLR-PLMN 620 includes GLR 625. VPLMN 630 includes MSC/VLRs 635, 640 and 645, and VPLMN 650 includes MSC/VLRs 655, 660 and 665. One skilled in the art will recognize that GLR 625 could also be located in one of the PLMNs which it serves. Similar to the situation described above with respect to FIG. 5, if a mobile subscriber who is being served by MSC/VLR 635 in VPLMN 630 roams into an area served by MSC/VLR 655 in VPLMN 650, GLR 625 would not request updated mobile subscriber information from HLR 615. Accordingly, GLR 625 will only have stored regional subscription restriction information which is relevant to VPLMN 630. GLR 625 will not have regional subscription restriction information which is relevant to VPLMN 650. The main difference between the networks illustrated in FIG. 5 and the one illustrated in FIG. 6 is that in the network of FIG. 5 both the CC and the NDC are different in different VPLMNs, while in the network of FIG. 6 only the NDC changes, the CC remains the same.
The introduction of a GLR which serves MSC/VLRs in a UMTS network also causes problems for mobile terminating short message service (MT-SMS). Using conventional MT-SMS procedures the GLR will not be completely transparent in the network. In the case of MT-SMS, the GLR has to interwork with the gateway mobile switching center (GMSC), which acts as a proxy for the MT-SMS messages, to deliver the SMS messages towards the mobile subscriber.
FIG. 7 illustrates a conventional GSM network. When mobile subscriber 725 moves from a location area which is being served by MSC/VLR 715 to a location area served by MSC/VLR 720, the mobile subscriber 725 initiates a location update with MSC/VLR 720. In response to the location update, MSC/VLR 720 sends a MAP_UPDATE_LOCATION message to HLR 710 which is associated with mobile subscriber 725. The MAP_UPDATE_LOCATION message includes, among other things, VLR Number (an E.164 number) and MSC Address. The HLR 710 sends a MAP_CANCEL_LOCATION message, including the IMSI of the mobile subscriber 725 to MSC/VLR 715 to inform MSC/VLR 715 that the mobile subscriber 725 has moved to a location area being served by another MSC/VLR. In addition, HLR 710 completes the location updating procedure with MSC/VLR 720.
FIG. 8 illustrates an exemplary network for routing MT-SMS messages. When an MT-SMS message is sent to mobile subscriber 840 the MT-SMS message is routed to SMS GMSC 810 in the mobile subscriber""s HPLMN. The SMS GMSC 810 requests the routing information from the HLR 820 via the MAP_SEND_ROUTING_INFORMATION_FOR_SMS message. The HLR 820 will provide the MSC address in a MAP_SEND_ROUTING_INFORMATION_FOR_SMS message so that the SMS GMSC 810 can forward the SMS message to MSC/VLR 830 which is currently serving mobile subscriber 840. MSC/VLR 830 will then forward the MT-SMS message to mobile subscriber 840.
FIG. 9 illustrates an exemplary UMTS network where GLR 910 is serving MSC/VLR 920 and MSC/VLR 930. As discussed above, when a mobile subscriber, such as mobile subscriber 960, roams for the first time into the VPLMN then MSC/VLR 930 will update the GLR 910 with its MSC/VLR identity (i.e., VLR number and MSC address) by sending the MAP_UPDATE_LOCATION message. The GLR 910 will detect that this is the first time that mobile subscriber 960 notifies itself within this VPLMN and will forward the MAP_UPDATE_LOCATION message to the HLR 940. The MAP_UPDATE_LOCATION message sent from GLR 910 to HLR 940 will include the GLR number and the address of GMSC 950. When mobile subscriber 960 roams into a location area served by MSC/VLR 920, MSC/VLR 920 sends the MAP_UPDATE_LOCATION message with the new MSC/VLR identity to GLR 910. GLR 910 recognizes that mobile subscriber 960 was already present within the VPLMN and will not forward the MAP_UPDATE_LOCATION message towards the HLR 940.
FIG. 10 illustrates an exemplary UMTS network for MT-SMS message routing where GLR 1040 serves a plurality of MSC/VLRs. When an MT-SMS message is sent to mobile subscriber 1060 the message is routed to SMS GMSC 1010 located in the mobile subscriber""s HPLMN. SMS GMSC 1010 will request the routing information from the HLR 1020 via the MAP_SEND_ROUTING_INFORMATION_FOR_SMS message. The HLR 1020 will provide address of GMSC 1030 which is serving the network which the mobile subscriber 1060 is currently located. SMS GMSC 1010 forwards the MAP_MT_FORWARD_SHORT_MESSAGE message to GMSC 1030. GMSC 1030 requests routing information from GLR 1040. Using the routing information provided by GLR 1040 the GMSC 1030 forwards the MAP_MT_FORWARD_SHORT_MESSAGE message to MSC/VLR 1050. MSC/VLR 1050 then forwards the MAP_MT_FORWARD_SHORT_MESSAGE message to mobile subscriber 1060.
There are several deficiencies to the MT-SMS message routing in the networks described above. First, the GMSC node introduces one additional hop in the path of the SMS messages, i.e., the SMS GMSC must route the MT-SMS message to the GMSC in the UMTS network of FIG. 10, whereas the SMS GMSC can route the MT-SMS message directly to the MSC/VLR in the GSM network of FIG. 8. Further, it is contemplated that the GMSC will be closely allocated to the GLR, preferably implemented on the same platform. In addition it is contemplated that the interworking serving generic packet radio service support node (I-SGSN) will be implemented on the same platform as the GLR to support the Network Initiated Packet Data Protocol (PDP). This will introduce a very complex platform that will contain a GLR, GMSC and an ISGSN. Also the GMSC will need to be enhanced to support functionality to terminate SMS messages, such as MAP_SEND_ROUTING_INFORMATION_FOR_SMS. Further, since the SMS GMSC will pack the IMSI into an SMS message parameter (SMS-DA) the GMSC needs to be enhanced to be able to unpack the SMS message to retrieve the IMSI.
The introduction of a GLR which serves serving generic packet radio service (GPRS) support nodes (SGSNs) in a UMTS network also causes problems when implementing GPRS. When implementing PDP in a UMTS network where a GLR serves a plurality of SGSNs the GLR may not be completely transparent to the other nodes in the network. In the case of GPRS the GLR has to take the role of the SGSN in addition to the role of the MSC/VLR. But since the SGSN is involved in the actual routing of data problems result.
FIG. 11 illustrates an exemplary GSM network for transferring packet data in a GSM network. The network includes an HLR 1110, SGSN 1120 and SGSN 1130. When mobile subscriber 1140 moves from a location area being served by SGSN 1120 to a location area being served by SGSN 1130, SGSN 1130 sends its identity, i.e., SGSN Number (an E.164 number) and SGSN Address (similar to an Internet Protocol (IP) address) to HLR 1110 via the MAP_UPDATE_GPRS_LOCATION message. HLR 1110 notifies SGSN 1120 that the mobile subscriber 1140 has roamed outside the area covered by SGSN 1120 via the MAP_CANCEL_LOCATION message. Further, HLR 1110 updates its subscriber records to indicate that mobile subscriber 1140 is currently being supported by SGSN 1130.
FIG. 12 illustrates the routing of packet data in an exemplary GSM network. The network includes an HLR 1210, a gateway GPRS signaling node (GGSN) 1220 and SGSN 1230. In a network initiated PDP context setup, mobile subscriber 1240 will be requested by the network to set up a PDP context so it can receive data packets. Data packets which are intended for mobile subscriber 1240 will be sent to GGSN 1220 which interfaces with HLR 1210 of mobile subscriber 1240. To enable GGSN 1220 to request that the mobile subscriber 1240 setup a PDP context, GGSN 1220 must know the SGSN address of the SGSN in whose service area the mobile subscriber 1240 is currently located. Accordingly, GGSN 1220 requests the routing information from HLR 1210 via the MAP_SEND_ROUTING_INFORMATION_FOR_GPRS message. HLR 1210 provides the address of SGSN 1230 to GGSN 1220. Using the address provided by HLR 1210, GGSN forwards the MAP_PDU_NOTIFICATION_REQUEST message via the SGSN 1230 to the mobile subscriber 1240.
FIG. 13 illustrates an exemplary UMTS network for packet data communication where a GLR serves a plurality of SGSNs. The network includes HLR 1310, GLR 1320, I-SGSN 1330, SGSN 1340 and SGSN 1350. When mobile subscriber 1360 roams for the first time into the VPLMN, SGSN 1340 updates GLR 1320 with its SGSN identity, i.e. SGSN number and SGSN address, by sending a MAP_UPDATE_GPRS_LOCATION message. GLR 1320 detects that this is the first time that the mobile subscriber notifies itself within this VPLMN, and GLR 1320 forwards a MAP_UPDATE_GPRS_LOCATION message to HLR 1310. Prior to forwarding the MAP_UPDATE_GPRS_LOCATION message, GLR 1320 replaces the SGSN identity with the GLR and I-SGSN identities, i.e. GLR number and ISGSN address.
When the mobile subscriber 1360 roams into a location area served by SGSN 1350, SGSN 1350 sends a MAP_UPDATE_GPRS_LOCATION message to GLR 1320 with the new SGSN identity. However, GLR 1320 recognizes that mobile subscriber 1360 was already present within the VPLMN and will not forward the MAP_UPDATE_GPRS_LOCATION message to HLR 1310. Accordingly, because of the introduction of the GLR to save signaling traffic between the HPLMN and VPLMN, the HLR will not contain the SGSN addresses but rather the address of the I-SGSN node that relays the packets to the SGSN which is currently serving the roaming mobile subscriber.
FIG. 14 illustrates the transfer of packet data to a roaming mobile subscriber in a UMTS network where a GLR serves a plurality of SGSNs. In a network initiated PDP context setup, the GGSN 1420 requests the routing information from HLR 1410 using a MAP_SEND_ROUTING_INFORMATION_FOR_GPRS message. HLR 1410 provides GGSN 1420 with the address of I-SGSN 1440. Using the address of I-SGSN 1440, GGSN 1420 forwards a MAP_PDU_NOTIFICATION_REQUEST message to I-SGSN 1440. I-SGSN 1440 requests routing information from GLR 1450. GLR 1450, based upon the information in its mobile subscriber records, provides the routing information of the SGSN which is currently serving mobile subscriber 1460. Using this routing information I-SGSN forwards the MAP_PDU_NOTIFICATION_REQUEST message to SGSN 1430. SGSN 1430 then delivers the PDU Notification Request to mobile subscriber 1460.
The introduction of a GLR which serves a plurality of MSC/VLRs in a UMTS network has various deficiencies. For example, the I-SGSN node introduces an additional hop with the path of the data packets. The additional hop results in an increased delay time within the data packets path. This increased delay time is problematic for delay sensitive applications, such as video or multi-media type applications. In addition, the I-SGSN, GLR, GMSC may be one the same platform which would result in a very complex platform.
Accordingly, it would be desirable to provide methods and apparatus for providing relevant regional subscription restriction data to MSC/VLRs in a network where a GLR serves MSC/VLRs in more than one country. Further, it would be desirable to provide methods and apparatus for providing relevant regional subscription restriction data to MSC/VLRs in a network where a GLR serves more than one network in a single country. In addition, it would be desirable to provide methods and apparatus for providing efficient MT SMS message routing in a network where a GLR serves a plurality of MSC/VLRs. It would also be desirable to provide efficient PDP context setup for routing packet data in a network which includes a GLR serving a plurality of SGSNs.
According to exemplary embodiments of the present invention, methods and apparatus are provided for providing regional subscription data to a serving visitor location register in a network where a gateway location register serves a first visitor location register in a first country and a second visitor location register in a second country. A location update is received from a mobile subscriber in a network. It is determined whether this is the first location update for the mobile subscriber in a network served by the gateway location register. It is also determined whether this is the first location update in a new country for the mobile subscriber. Regional subscription data is requested from a home location register associated with the mobile subscriber if the location update is not the first location update for the mobile subscriber in the network and if the location update is the first location update for the mobile subscriber in the new country.
In accordance with another aspect of the present invention, methods and apparatus are provided for providing regional subscription data to a serving visitor location register in a network where a gateway location register serves a first visitor location register in a first network and a second visitor location register in a second network, the first and second networks being located in a same country. A location update is received from a mobile subscriber in a network. It is determined whether this is the first location update for the mobile subscriber in the first and second networks. It is also determined whether this is the first location update for the mobile subscriber in a new network served by the gateway location register. Regional subscription data is requested from a home location register associated with the mobile subscriber if the location update is not the first location update for the mobile subscriber in the first and second networks and if the location update is the first location update for the mobile subscriber in the new network.
In accordance with yet another aspect of the present invention, methods and apparatus are provided for delivering short message service messages to a mobile subscriber located in a visited network in a network where a gateway location register serves a visitor location register. An indication is provided to a home location register associated with the mobile subscriber that the gateway location register is present in the visited network. An address of a mobile switching center which is serving the mobile subscriber in the visited network is requested from the gateway location register.
In accordance with a further aspect of the present invention, methods and apparatus are provided for delivering packet data to a mobile subscriber located in a visited network in a network where a gateway location register serves a serving support node. An indication is provided to a home location register associated with the mobile subscriber that the gateway location register is present in the visited network. An address of a serving support node which is serving the mobile subscriber in the visited network is requested from the gateway location register.